CBLM_Identifying Different Kinds of Technical Drawings

ACHIEVING COMPETENCE IN PREPARING/INTERPRETING TECHNICAL DRAWING

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IDENTIFYING DIFFERENT KINDS OF TECHNICAL DRAWINGS

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This is the first of the modular series produced by the Jacobo Z. Gonzales Memorial School of Arts and Trades – Technical Education and Skills Development Authority Region IV-A

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Prepare/Interpret Technical Drawing

Version No.: 2 Date: August 10, 2009 By: Glenn F. Salandanan Page 1 of 17

TABLE OF CONTENTS

Content

Page Number

LEARNING GUIDE OVERVIEW ........................................................................ 3

II.

HOW TO USE THIS GUIDE ............................................................................... 4

III.

LEARNING ACTIVITIES ..................................................................................... 5

IV.

INFORMATION SHEET 1: TYPES OF DRAWINGS, VIEWS AND PERSPECTIVES

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I.

A. CATEGORIES OF DRAWINGS .................................................................... 6

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B. VIEWS AND PERSPECTIVES ..................................................................... 8 INFORMATION SHEET 2: TYPES OF DRAWING PROJECTIONS

C. PICTORIAL DRAWING ............................................................................... 11 D. ORTHOGRAPHIC PROJECTIONS ............................................................ 12 SELF CHECK 1 ................................................................................................ 10

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V.

SELF-CHECK 2 ................................................................................................ 13 ANSWER KEYS ......................................................................................... 14-15

VII.

RECORD OF COMPETENCE .......................................................................... 17

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VI.

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LEARNING GUIDE OVERVIEW

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The entire world depends upon technical drawings to convey the ideas that feed today’s industrialized society. Architectural, structural, electric, electronic, machine, plumbing, and piping drawings are all forms of mechanical/technical drawings. When rendering technical drawings, accuracy, neatness, technique, and speed in execution are essential. Inaccurate drawings could be worthless or lead to costly errors. In this learning material, the students should be able to identify the different types of drawings, views, perspectives, and drawing projections. Competencies will be demonstrated by completing the self-checks and the unit test with a minimum score of 75 percent.

When you have successfully completed the learning activities in this material, you will be able to: 1. Identify the different types of drawings, views and perspectives 2. Identify different types of drawing projections

CONTENTS

This learning material includes the following: 1. Types of drawings, views and perspectives 2. Types of drawing projections

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OBJECTIVES

PRE-REQUISITES

The completion of this learning material requires you to have a basic understanding of:

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If you are unfamiliar with any of the above concepts, work on________ before working on this learning guide.

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HOW TO USE THIS LEARNING GUIDE This Learning Guide will lead you through a series of activities which will require you to work at your own pace. These activities will ask you to complete associated learning and practice activities in order to gain the knowledge and skills you need to achieve the learning objectives stated earlier.

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Refer to Learning Activity Page to know the sequence of learning tasks to undergo and the appropriate resources to use in each task. This page will serve as your road map towards the achievement of objectives. Read the information sheets. This will give you an understanding of the work, and why things are done the way they are.

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Complete the activities as directed in the activity/practice sheets. These will test your knowledge and give you practice of doing the tasks involved. Performance criteria for assessing practical exercise are shown to guide you in undertaking the practical exercises. Always be aware of safety requirements highlighted in this material. Ask for clearance in using some tools and equipment. Should you require some assistance and clarification, consult your trainer or facilitator. They should be available anytime you need them.

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Answer self-checks found in each section of the learning guide. Do not write anything on this learning guide; provide separate sheets for your answers. Self-checks will let you know how you are going. To know how you fared with self checks, review the answer keys found at the end of the learning guide. When you had completed all the tasks required in this learning guide, an assessment exercise will be given to evaluate if you are already competent with the specified learning outcomes in and ready for the next task. .If you feel ready for the assessment, consult the facilitator.

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A record of competency is provided on the last page to reflect how much of the required assessment criteria have been met.

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You may already have some or most of the knowledge and skills covered in this learner’s guide. Talk to your trainer about having them formally recognized. If you have qualification or certificate of competence from previous training, show it to your trainer. If the skills you acquired are still current and relevant to the unit of competency they may become part of the evidence you can present for Recognition of Prior Learning (RPL). If you are not sure about the accuracy of your skills, discuss it with your trainer.

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LEARNING ACTIVITIES In order to accomplish the objectives stated in this leaning guide, you must perform the learning steps below. Beside each step are the resources or special instructions you will use to accomplish the corresponding activity.

RESOURCES/SPECIFIC INSTRUCTIONS

LEARNING STEPS Student will ask the instructor of the

1.

materials to be used

Instructor will provide the learning materials in Identifying Different Kinds of

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1.

Technical Drawing

2.

Read: Information Sheet No. 1

2.

Information Sheet No 1: Types of

3.

Answer: Self Check 1

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Drawings, views and Perspectives

3.

Self Check: Types of Drawings, views

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and Perspectives

Read: Information Sheet No. 2

4.

Information Sheet No. 2: Types of Drawing Projection

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Answer: Self Check 2

5.

Self

Check

2:

Types

of

Drawing

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Projection

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INFORMATION SHEET NO: 1 TYPES OF DRAWINGS, VIEWS AND PERSPECTIVES A. Categories of Drawings

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This introduces the five common categories of drawings. They are: 1. Piping and instrument drawings (P&IDs) 2. Electrical single lines and schematics 3. Electronic diagrams and schematics 4. Logic diagrams and prints 5. Fabrication, construction, and architectural drawings

1. Piping and Instrument Drawings (P&IDs)

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• present functional information about a system or component ex. piping layout flowpaths pumps valves instruments signal modifiers controllers • do not have a drawing scale • present only the relationship or sequence between • present information on how a system functions, not the actual physical relationships

Figure 1. Example of P&ID

2. Electrical Single Lines and Schematics

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a. Electrical Single Line • designed to present functional information about the electrical design of a system or component • provide the same types of information about electrical systems that P&IDs provide for piping and instrument systems • electrical prints are not usually drawn to scale Examples of electrical single line are site or building power distribution, system power distribution, motor control centers

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Figure 2. Example of Single-line



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Figure 3. Example of Schematic

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b. Electrical Schematics • provide a more detailed level of information about an electrical system or component • present information such as the individual relays, relay contacts, fuses, motors, lights, and instrument sensors Examples of typical schematics are valve actuating circuits, motor start circuits, and breaker circuits

3. Electronic Diagrams and Schematics

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present information about the individual components (resistors, transistors, and capacitors) used in a circuit, as illustrated in Figure 4 used by circuit designers and electronics repair personnel

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Figure 4. Example of Schematic Diagram

4. Logic Diagrams and Prints • •

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depict several types of information provide a simplified functional representation of an electrical circuit, as illustrated in Figure 10 do not replace schematics, but they are easier to use for certain applications

Figure 5. Example of Logic Print

5. Fabrication, Construction, and Architectural Drawings • •

present the detailed information required to construct or fabricate a part, system, or structure construction drawings/ blueprint drawings present the detailed information required to assemble a structure on site

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• •

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architectural drawings present information about the conceptual design of the building or structure fabrication drawings are found in machine shops and provide the necessary detailed information for a craftsman to fabricate a part drawn to scale

Figure 6. Example of a Fabrication Drawing

B. Views and Perspectives

In addition to the different drawing formats, there are different views or perspectives in which the formats can be drawn. The most commonly used are the orthographic projection and the isometric projection.

1. Orthographic Projections

widely used for fabrication and construction type drawings, as shown in Figure 16 present the component or system through the use of three views: o top view o side view o front view

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Figure 7. Orthographic Projection

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drawn to scale and shows all components in their proper relationships to each other

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contain information that is necessary to fabricate or construct the component or system

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2. Isometric Projection

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single view of the component or system view is commonly from above and at an angle of 30° more realistic three dimensional view this view makes it easier to see how the system looks and how its various portions or parts are related to one another may or may not be drawn to a scale

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Figure 8. Orthographic Projection

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Figure 9. Example of an Isometric



SELF- CHECK NO. 1 Check your mastery in identifying different kinds of technical drawing by completing the tasks below.

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IDENTIFICATION. Identify the kind of technical drawing shown below by writing your answer on the space provided.

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1.______________________________

3. ___________________________

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3.

2.______________________________

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4.___________________________

5.____________________________

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INFORMATION SHEET NO: 2 TYPES OF DRAWING PROJECTIONS A. Pictorial Drawing

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The pictorial drawings are non-specific but provide visualization. They can be subdivided further into perspective, axonometric and oblique projections. In pictorial projections, an object is represented as it is seen in 3D but on 2D paper.

Types of Pictorial Drawing

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a. Axonometric Drawing- A type of pictorial with each of the three planes and axes at any angle and not equal to 90°. The three types of axonometric drawing are as follows: 1. Isometric – A type of axonometric drawing with each of the three planes and axes equal to each other 2. Dimetric – A type of axonometric drawing with two planes on equal axes to each other and a third plane of a different angle 3. Trimetric – A type of axonometric drawing with all three planes and axes not equal to each other

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Figure 100. Types of axonometric drawing

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b. Oblique Drawing - A type of pictorial drawing with front plane true size and parallel to frontal plane, the other two at any angle to the front. The two types of oblique drawing are as follows: 1. Cavalier – A type of oblique drawing with all axis lines drawn at the same scale 2. Cabinet – A type of oblique drawing with the depth axis drawn half scale and the other axis lines drawn full scale

Figure 11. Oblique drawing of a bearing kit

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c. Perspective Drawing - A perspective drawing is the most used method of presentation used in technical illustrations in the commercial and architectural fields. The drawn objects appear proportionately smaller with distance, as they do when you look at the real object (see Fig. 12). It is difficult to draw, and since the drawings are drawn in diminishing proportion to the edges represented, they cannot be used to manufacture an object.

B. Orthographic Projections

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Figure 112. Perspective drawing

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Orthographic Projection is a way of drawing an object from different directions. Usually, front, side and top views are drawn so that a person looking at the drawing can see all the important sides. Orthographic drawings are useful especially when a design has been developed to a stage whereby it is almost ready to manufacture. Orthographic projections can be subdivided into first and third angle projections. The difference between the two is how the object is projected and the position of the views on the drawing.

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a. Third Angle Projections- Third-angle projection is used in the United States and Canada. The projection plane is considered to be between the viewer and the object, and the views are projected forward to that plane. The top view appears above the front view, the right-side view is to the right of the front view, the left view to the left of the front view, and so on.

Figure 13. Views are projected forward in third-angle projection

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b. First Angle Projections- Most European countries use first-angle projection. In firstangle projection, the projection plane is on the far side of the object from the viewer. The views of the object are projected to the rear and onto the projection plane instead of being projected forward.

Figure 14. Views are projected backward in first-angle projection

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Carefully study the symbols shown below. Normally when drawing in first or thirdangle projection a symbol is drawn underneath that clearly shows which angle of projection has been used.

Figure 15. Symbol for first-angle and third-angle projection

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The final arrangements of the views are shown in the drawing below. Notice how the symbol for first angle orthographic projection has been added to the drawing.

Figure 16. Symbol for first-angle projection has been added to the drawing

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SELF- CHECK NO. 2 Check your mastery in types of drawing projections by completing the tasks below. I. Multiple Choice. Write only the letter that corresponds to your answer.

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1. A type of axonometric drawing with each of the three planes and axes equal to each other. a. Isometric drawing b. Dimetric drawing c. Trimetric drawing 2. A type of pictorial drawing with front plane true size and parallel to frontal plane, the other two at any angle to the front. a. Axonometric drawing b. Oblique drawing c. Perspective drawing 3. A type of drawing used in technical illustrations in the commercial and architectural fields. a. Axonometric drawing b. Oblique drawing c. Perspective drawing 4. A type of pictorial with each of the three planes and axes at any angle and not equal to 90° a. Axonometric drawing b. Oblique drawing c. Perspective drawing II. Fill in the Blanks. Supply the following statements with the missing term to complete its thought.

Orthographic drawing is a way of drawing an object from different ______________. 6. The difference between first-angle and third-angle projection is how the object is projected and the ________________ of the views on the drawing. 7. In _______________ projection, the projection plane is considered to be between the viewer and the object, and the views are projected forward to that plane. 8. The views in ________________ projection, the projection plane is on the far side of the object from the viewer. 9-10. Identify the symbol of first and third-angle projection

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a. ________________

b. _______________



ANSWER KEY NO. 1 Check your answer with the answer key below. If you fail to get it right, refer back to corresponding resources until you make it perfect. 1. Logic Diagrams and Prints 2. Fabrication Drawing

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3. Electrical Schematics 4. Piping and Instrument Drawing

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5. Schematic Diagram

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ANSWER KEY NO. 2 Check your answer with the answer key below. If you fail to get it right, refer back to corresponding resources until you make it perfect. I. 1. A

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2. B 3. C 4. A II. 5. Directions 7. Third angle Projection 8. First angle Projection 9. a. First angle Projection

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6. Position

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b. Third angle Projection

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RECORD OF COMPETENCE Below are your assessment ratings:

ASSESSMENT /PERFORMANCE CRITERIA

YES

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1. Correct technical drawing

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selected according to job requirements

2. Technical drawings segregated

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in accordance with the types and kinds of drawings

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CBLM_Identifying Different Kinds of Technical Drawings

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